I'm looking to create a bootable USB memory stick. However the USB stick has data that I can't afford to delete. If I were to burn an iso image on it the ordinary way, say with Ultraiso, the data will be lost.

My idea is to copy the contents of the bootable iso image directly onto the USB stick, (including the boot loader files), and then make it an "Active" partition, I guess that would solve MBR issue. However that doesn't seem to work.

What am I missing here?

Note that my question is in general here, and not about a particular bootable software.

  • What kind of iso are you trying to make bootable on your USB stick? Windows or Linux? Mar 24, 2014 at 9:11
  • @TarekJellali Neither. I have tried with system restore disk, Acronis boot disk, Seatools for DOS, Active boot disk, etc.. I always had this problem, so I need a general way, or better understand the process even with programs I might encounter in the future.
    – Ray
    Mar 24, 2014 at 10:05

2 Answers 2


You can install grub2 on the USB device.
Then you can use grub2 to boot bootable ISO files directly. For this purpose you can either extract linux kernel from the ISO or you can make use of the "loopback" feature of grub2. here is an example to boot ubuntu
For ISOs that cannot be booted this way, you can then try memdisk.

  • What is grub? Please provide a download link. Can it work with; system restore disk, Acronis boot disk, Seatools for DOS, or Active boot disk?
    – Ray
    Mar 24, 2014 at 10:07
  • oh, if you don't know what a grub is, you better not use this approach. try yumi instead. pendrivelinux.com/yumi-multiboot-usb-creator. Mar 25, 2014 at 6:49
  • Thank you. Yumy works great. One more thing though, when the distribution is not supported in the list, can the "Try unlisted ISO (GRUB)" work as a general case? If not, please explain.
    – Ray
    Mar 25, 2014 at 14:17
  • Of course you can use the option "Try unlisted ISO (GRUB)", but there's no guarantee it'll work. I guess it depends on the ISO itself. Mar 26, 2014 at 2:39

You can try

bootsect /nt60 <driveletter>: /force /mbr

Update: To be able to boot from disk the following requirements must be met.

  1. The disk must be selected as boot source in bios.
  2. Disk must contain valid MBR (first sector of disk).
  3. Disk must contain partition marked as active.
  4. Active partition must contain Bootsector that can load bootloader. Different bootsectors for different bootloaders. Windows XP bootsector is called nt52, Windows Vista and higher is called nt60.
  5. Bootloader must be in the root of partition's filesystem. Windows XP bootloader is called NTLDR, Windows Vista and higher is called bootmgr

To mark partition as active you can use diskpart. It is bundled with every Windows.

To write MBR and Bootsector, you can use tool bootsect. It is bundled to Windows 8. In earlier windows it is part of recovery envirnment, but you can download it from internet.

Bootloader is just a file, so you will copy it when extract ISO image to USB strick

  • Could you provide more details please
    – Ray
    Mar 24, 2014 at 11:02
  • +1 for the info. I believe I have done 1&3&5 correctly. The bootsect requirement seems to be what's missing. I hope you would provide some guide lines on to how to use this tool and a dwld link would be deeply appreciated. I have done some googling but turned out unfruitful and a bit confusing; technet.microsoft.com/en-us/library/cc749177%28v=ws.10%29.aspx. Please note that I seek a method for non-OS bootables as well. Refer to comment below original OP.
    – Ray
    Mar 25, 2014 at 16:58

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .